Available-for-Sale Securities and Fair Value Measurements (Tables)

9 Months Ended

Sep. 30, 2016

Available-for-Sale Securities and Fair Value Measurements

Schedule of available-for-sale securities

(In thousands)	September 30, 2016		December 31, 2015
Cash and cash equivalents	$	90,696	$	148,673
Short-term marketable securities	55,772		28,103
Total	$	146,468	$	176,776

Schedule of amortized cost and estimated fair values for available-for-sale securities

	September 30, 2016
(In thousands)	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses		Estimated Fair Value
U.S. government agencies	$	19,913	$	8	$	—	$	19,921
U.S. commercial paper	64,838		—		—		64,838
Money market funds	61,709		—		—		61,709
Total	$	146,460	$	8	$	—	$	146,468

	December 31, 2015
(In thousands)	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses			Estimated Fair Value
U.S. government agencies	$	14,406	$	—	$	(1	)	$	14,405
U.S. corporate notes	2,702		—		(1		)	2,701
U.S. commercial paper	10,997		—		—			10,997
Money market funds	148,673		—		—			148,673
Total	$	176,778	$	—	$	(2	)	$	176,776

Schedule of estimated fair values

	Estimated Fair Value Measurements as of September 30, 2016 Using:
Types of Instruments	Quoted Price in Active Markets for Identical Assets		Significant Other Observable Inputs		Significant Unobservable Inputs
(In thousands)	Level 1		Level 2		Level 3		Total
Assets
U.S. government agencies	$	—	$	19,921	$	—	$	19,921
U.S. commercial paper	—		64,838		—		64,838
Money market funds	61,709		—		—		61,709
Total assets measured at estimated fair value	$	61,709	$	84,759	$	—	$	146,468
Liabilities
Convertible subordinated notes due 2023	$	—	$	206,798	$	—	$	206,798
Non-recourse notes due 2029	—		490,740		—		490,740
Total fair value of liabilities	$	—	$	697,538	$	—	$	697,538

	Estimated Fair Value Measurements as of December 31, 2015 Using:
Types of Instruments	Quoted Price in Active Markets for Identical Assets		Significant Other Observable Inputs		Significant Unobservable Inputs
(In thousands)	Level 1		Level 2		Level 3		Total
Assets
U.S. government agencies	$	—	$	14,405	$	—	$	14,405
U.S. corporate notes	—		2,701		—		2,701
U.S. commercial paper	—		10,997		—		10,997
Money market funds	148,673		—		—		148,673
Total assets measured at estimated fair value	$	148,673	$	28,103	$	—	$	176,776
Liabilities
Convertible subordinated notes due 2023	$	—	$	189,100	$	—	$	189,100
Non-recourse notes due 2029	—		470,970		—		470,970
Total fair value of liabilities	$	—	$	660,070	$	—	$	660,070